mysql半同步复制

1、首先在master上面安装插件

INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so';
Query OK, 0 rows affected (0.01 sec)

2、设置master全局变量和超时时间

SET GLOBAL rpl_semi_sync_master_enabled = 1;
Query OK, 0 rows affected (0.00 sec)
查看变量是否开启 
show variables like "%semi_sync%";
+-------------------------------------------+------------+
| Variable_name                             | Value      |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled              | ON         |
| rpl_semi_sync_master_timeout              | 10000      |
| rpl_semi_sync_master_trace_level          | 32         |
| rpl_semi_sync_master_wait_for_slave_count | 1          |
| rpl_semi_sync_master_wait_no_slave        | ON         |
| rpl_semi_sync_master_wait_point           | AFTER_SYNC |
+-------------------------------------------+------------+
6 rows in set (0.01 sec)

3、在slave上面安装插件，设置全局变量

INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so';
Query OK, 0 rows affected (0.00 sec)
SET GLOBAL rpl_semi_sync_slave_enabled = 1;
Query OK, 0 rows affected (0.00 sec)

4、停止slave上面的I/O线程，然后重启I/O线程

STOP SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)
 
START SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)

5、也可以在配置文件里面配置半同步复制（永久开启）

master： 
[mysqld]
rpl_semi_sync_master_enabled=1
rpl_semi_sync_master_timeout=1000 # 1 second
slave：
[mysqld]
rpl_semi_sync_slave_enabled=1

6、测试数据一致性

create database test;
Query OK, 1 row affected (1.01 sec)
 
show databases;
+--------------------+
| Database           |
+--------------------+
| test               |

use test;
Database changed
show tables;
Empty set (0.00 sec)
 
create table tt1(id int,name varchar(10));
Query OK, 0 rows affected (0.00 sec)

show tables;
+----------------------+
| Tables_in_zhaojunjie |
+----------------------+
| tt1                  |
+----------------------+
1 row in set (0.00 sec)

在slave上面：可以看到数据同步过来了，说明数据一致

show databases;
+--------------------+
| Database           |
+--------------------+
| test               |
+--------------------+
11 rows in set (0.00 sec)
 
use test;
Database changed
show tables;
Empty set (0.00 sec)
show tables;
+----------------------+
| Tables_in_zhaojunjie |
+----------------------+
| tt1                  |
+----------------------+
1 row in set (0.00 sec)